Tomorrow the moon will pass directly between the sun and Earth at 6:52pm EST, causing an annular solar eclipse, where only a ring of sunlight will be visible circling the edge of the moon. This is not to be missed as it's the first annular solar eclipse viewable from the USA since May 10, 1994.

But you should know that it's extremely dangerous to look at the sun even if most of its light is obscured by the moon. Just as a magnifying glass can focus enough sunlight onto a leaf to start a fire, the lens in your eye can also focus that sliver of light onto your retina to burn it. And because retinas have no pain receptors, you can permanently damage your vision without even feeling it happen!

DO NOT LOOK AT THE SUN DURING A SOLAR ECLIPSE!

That's not to say you can't watch it indirectly though. Let's make a simple pinhole camera. To build one, all you need are a few household supplies:

A box (upcycle or recycle if possible)

small piece of tinfoil

white sheet of paper

tape

pin or needle

box cutter or Xacto knife
Packing tape or other

Tape a piece of white paper to the inside of the box, at the opposite end from where the foil covered hole will be. The paper should be positioned so that light entering the box through the pin hole will hit it. This is where you'll look for the sun.

Cut a small hole about 1 inch across on the opposite end of the shoe box near an edge.

Cut a 1 inch diameter hole caddy corner to the hole you just cut.

Tape a piece of foil over the first cut hole.

Using a pin or needle, punch a hole in the center of the foil.

Tape up the box.

When the time comes to watch the eclipse, hold the box so that it lines up with it's own shadow, demonstrating that it is aligned with light from the sun. Stand so that when you look through the viewing hole, you can see a tiny bead of light on the image screen - that's the sun. During the eclipse, you'll see the shadow of the moon pass in front of the sun.